Mathematical and Theoretical Physics Seminar: Divij Gupta (UIUC), "Entanglement, Evaporation, and beyond: HRT in asymptotically flat spacetimes"
- Event Type
- Seminar/Symposium
- Sponsor
- Department of Physics
- Location
- Loomis 464
- Date
- Dec 4, 2025 1:00 - 2:00 pm
- Speaker
- Divij Gupta
- Contact
- Thierry Ramais
- ramais@illinois.edu
- Phone
- 217-300-2044
- Views
- 40
- Originating Calendar
- Physics - Mathematical and Theoretical Physics Seminar
Abstract: We propose a generalization of the RT and HRT holographic entanglement entropy formulas to spacetimes with asymptotically Minkowski as well as asymptotically AdS regions. We postulate that such spacetimes represent entangled states in a tensor product of Hilbert spaces, each corresponding to one asymptotic region. We show that our conjectured formula has the same general properties and passes the same general tests as the standard HRT formula. We provide further evidence for it by showing that in many cases the Minkowski asymptotic regions can be replaced by AdS ones using a domain wall. We illustrate the use of our formula by calculating entanglement entropies between asymptotic regions in Brill-Lindquist spacetimes, which are then used to construct a holographic model of black hole evaporation in four-dimensional asymptotically flat spacetimes. Applying HRT we compute the entanglement entropy, which is shown to obey the Page curve, consistent with information conservation. Index-1 surfaces in the wormhole interior are interpreted as candidate bulges involved in the python's lunch conjecture, and their areas are used to compute the (restricted) complexity of decoding the Hawking radiation. Finally, we discuss a variety of possible extensions and generalisations, including to universes with asymptotically de Sitter regions.